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Repeatedly you hear the claim that August Weismann refuted Jean Lamarck's evolutionary concept of inheritance of acquired characteristics, by chopping off mouse tails for generations and viola, the tail remained in the subsequent generations despite the fact it was chopped off (how painful!) over and over again.
However, this is a myth and here is why.
Lamarck taught many things but to simplify one of his core ideas, it is that if a particular organ has not been used over a long period of time, then it will eventually fade away and disappear, like the color of your cloth, it fades away. The difference between the color of the cloth and an organ fading away is the length of time it requires to fade. For Lamarck, he hypothesized that it would've taken an unimaginably long time for that to happen. This is where Weismann himself realized he was mistaken because he did not experiment for a long time (he only lived for 80 years).
As Stephen Jay Gould mentioned, Weismann did do the experiments but Weismann also noticed it did "little to combat Lamarckism"[1]
So what made Weismann disagree with Lamarck's view? The answer lies in the understanding of, what we call now, genetic inheritance. For Lamarck's theory to work, the environment must affect the genetic inheritance but according to Weismann, hereditary was passed on to generations without any influence from the environment. Since that is the case, Lamarck's theory becomes futile. However, today, there is a form of Lamarckian resurrection since there is evidence that the environment can affect the DNA and other genetic materials.
Also, if a short-term experiment can refute a theory that requires a long period of time, then by the same token, Darwinism (and all its forms) would easily be refuted as well since there are no observed large changes. A dog remains a dog no matter how many times a dog is bred. In reality, if the mouse experiment constitutes as evidence against Lamarckism then every other evolutionary theory becomes futile. It's a double-edged sword to use the mouse experiment against Lamarckism.
Reference(s)
[1] Gould, Stephen Jay. 2002. The Structure of Evolutionary Theory. Page 201.
Repeatedly you hear the claim that August Weismann refuted Jean Lamarck's evolutionary concept of inheritance of acquired characteristics, by chopping off mouse tails for generations and viola, the tail remained in the subsequent generations despite the fact it was chopped off (how painful!) over and over again.
However, this is a myth and here is why.
Lamarck taught many things but to simplify one of his core ideas, it is that if a particular organ has not been used over a long period of time, then it will eventually fade away and disappear, like the color of your cloth, it fades away. The difference between the color of the cloth and an organ fading away is the length of time it requires to fade. For Lamarck, he hypothesized that it would've taken an unimaginably long time for that to happen. This is where Weismann himself realized he was mistaken because he did not experiment for a long time (he only lived for 80 years).
As Stephen Jay Gould mentioned, Weismann did do the experiments but Weismann also noticed it did "little to combat Lamarckism"[1]
So what made Weismann disagree with Lamarck's view? The answer lies in the understanding of, what we call now, genetic inheritance. For Lamarck's theory to work, the environment must affect the genetic inheritance but according to Weismann, hereditary was passed on to generations without any influence from the environment. Since that is the case, Lamarck's theory becomes futile. However, today, there is a form of Lamarckian resurrection since there is evidence that the environment can affect the DNA and other genetic materials.
Also, if a short-term experiment can refute a theory that requires a long period of time, then by the same token, Darwinism (and all its forms) would easily be refuted as well since there are no observed large changes. A dog remains a dog no matter how many times a dog is bred. In reality, if the mouse experiment constitutes as evidence against Lamarckism then every other evolutionary theory becomes futile. It's a double-edged sword to use the mouse experiment against Lamarckism.
Reference(s)
[1] Gould, Stephen Jay. 2002. The Structure of Evolutionary Theory. Page 201.
